mime base64 revisited

[sen_ml at eccosys dot com]

i'd like to be able to do base64 (mime) maniuplations in guile.

before returning to the exercise of doing multiple implementations in
scheme, i'd like to try the swig approach.  i've looked for some base64
manipulation libraries, and have come up w/:

  http://ruby.ddiworld.com/jreed/web/software/libbase64.html (c++)
  http://www.fourmilab.ch/webtools/base64/ (c -- didn't compile as-is on linux)

i've also looked at what perl and python do -- python has a c module
named binascii which provides relevant routines, and perl (at least
the MIME-base64 module) uses xs.  it looks to me as if neither are
usable for guile w/o modification.

can anyone recommend a base64 library?  or perhaps something which is
more general?

thanks for any help.